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https://issues.apache.org/jira/browse/HDFS-7214?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14596326#comment-14596326
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Haohui Mai commented on HDFS-7214:
----------------------------------
Thanks for working on this.
{code}
-
+ /** the time when the namenode became active */
+ private volatile long activeStateStartTime;
{code}
This is a read-dominant workload. It makes more sense to use {{AtomicLong}}
here. You can call {{lazySet()}} to update the timestamp.
{code}
+ @Override // NameNodeStatusMXBean
+ public String getNNTransitToActiveTime() {
+ if (activeStateStartTime == 0) {
+ return "N/A";
+ }
+ return new Date(activeStateStartTime).toString();
+ }
+
{code}
It might be better to return the timestamp and let the UI to format the date,
considering locales and timezone issues.
> Display the time when NN became active on the webUI
> ---------------------------------------------------
>
> Key: HDFS-7214
> URL: https://issues.apache.org/jira/browse/HDFS-7214
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Siqi Li
> Assignee: Siqi Li
> Labels: BB2015-05-TBR
> Attachments: HDFS-7214.v1.patch, HDFS-7214.v2.patch,
> HDFS-7214.v3.patch
>
>
> The currently NN webUI displayed JVM start up. It will be useful to show when
> NN became active.
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